Functionalized quaternary ammonium halides and use thereof

ABSTRACT

Various embodiments relate generally to the preparation of functional quaternary ammonium salts. More particularly, various embodiments relate to the preparation of hydroxyl group functionalized quaternary ammonium halides. Various embodiments also relate to the preparation of photocurable quaternary ammonium halides from the hydroxyl group functionalized quaternary ammonium halides. In other embodiments, preparation of hydrolytically curable quaternary ammonium halide derivatives by a sol-gel process is also disclosed. Said hydroxyl group functionalized quaternary ammonium halides are useful for making polymers, which are useful as water insoluble, non-leaching, active by contact antifouling materials.

TECHNICAL FIELD

Various embodiments relate generally to the preparation of functionalquaternary ammonium salts. More particularly, various embodiments relateto the preparation of hydroxyl group functionalized quaternary ammoniumhalides. Various embodiments also relate to the preparation ofphotocurable quaternary ammonium halides from the hydroxyl groupfunctionalized quaternary ammonium halides. In other embodiments,preparation of hydrolytically curable quaternary ammonium halidederivatives by a sol-gel process is also disclosed. Said hydroxyl groupfunctionalized quaternary ammonium halides are useful for makingpolymers, which are useful as water insoluble, non-leaching, active bycontact antifouling materials.

BACKGROUND

Quaternary ammonium salts have many applications such as ion exchangeresins, phase transfer catalysts, structure directing agents in thepreparation of zeolites, components of cosmetics & personal careformulations, photovoltaic cells, flocculating agents for waterpurification applications, antimicrobial agents, antistatic agents, etc.Earliest reports on quaternary ammonium salt bearing polymers, which aresometimes referred to as polyionenes, date back to early 1930s.Quaternary ammonium salts are well known cationic disinfectants andtheir bactericidal properties are known for many decades. Quaternaryammonium salts which are attached to polymers and are thus made waterinsoluble biocides have many advantages. These water insoluble biocidesare non-leaching in nature and thus their activity is retained forlonger periods of time than biocides that function by leaching. Sinceleaching causes environmental concerns due to the fact that it releasestoxic compounds, biocides which possess biocidal activity by contact aretherefore more preferred.

One of the problems facing man-made structures immersed in water is theunwanted settlement and growth of water borne organisms. This process,which is referred to as biofouling, is caused by both micro- andmacro-organisms. Biofouling leads to many problems ranging from poorperformance of materials, shortened durability, increased weight anddrag on water bound moving vehicles such as ships which cause higherfuel consumption as well as transport of marine organisms from onegeographical location to another, a phenomenon called species invasion.Until recently, the problem of biofouling was tackled by the use ofheavy metal leaching coatings which have caused environmental problems.As an alternative to this, quaternary ammonium salt bearing compoundshave been proposed as suitable environmentally friendly alternatives.

U.S. Pat. Nos. 4,891,166 and 5,235,082 disclose polysiloxane ionomerswith quaternary ammonium salt groups. These quaternary ammonium chlorideunits improve the compatibility of polysiloxanes with organic polymersand introduce antimicrobial and anti-electrostatic properties to thematerials to make them applicable for fabric conditioning agents,bactericides, textile finishing and plastic processing. U.S. Pat. No.4,818,797 disclose ammonium carboxylates. WO 9951694 disclosesdenatonium capsaicinate and WO 9109915 disclose quaternary ammoniumsalts derived from sulfonic acids. U.S. Pat. No. 6,727,387 disclosequaternary ammonium salts having tertiary alkyl groups. U.S. Pat. No.6,479,566 discloses the preparation of acid groups blocked by quaternaryammonium groups. U.S. Pat. No. 7,598,299 disclose quaternary ammoniumsalts formed with palmitate. U.S. Pat. No. 4,128,429 disclose quaternaryammonium salts of benzyl bromide and tertiary amines containing tributylstannyl ether moiety. U.S. Pat. No. 6,008,244 discloses a halopropargylammonium compound. U.S. Pat. Nos. 8,278,400 and 8,372,384 disclosequaternary ammonium salt functionalized crosslinked polyalkylsiloxanes.

Quaternary ammonium salts have been grafted onto polyvinyl chloride andcoatings prepared from such polymers exhibited better biocidalproperties than classical paints containing organo tin compounds duringtwo months in sea water. However, the efficiency decreased after thisperiod (J. Hazziza-Laskar et al., J. Appl. Polym. Sci. (1993) 50,651-662). Bioactivity of quaternary ammonium salts was determined bycontact and diffusion processes (N. Nurdin et al. J. Appl. Polym. Sci.(1993) 50, 663-670). Bioactivity was measured in linear alkyl bromidesfrom C₈ to C₁₆ carbon atoms. After 1 h, the bioactivity measured waspractically independent of the length of the alkyl chain. For chainswith 12, 14 and 16 carbon atoms the coatings exhibited no diffusionthereby confirming activity by contact whereas for 8 and 10 carbon atomsa zone of inhibition was observed. The location of the quaternaryammonium salt at the free extremity of a flexible side chain is a veryimportant factor. Polymers bearing pendant quaternary ammonium salts areuseful for formulating new biocidal coatings that have the advantage ofbeing non-polluting. More importantly, the activity may be permanentbecause the biocidal group is not consumed during the course ofinteraction with microorganisms. This is contrary to leaching where lossof activity with time is accompanied with environmental problems causedby the high toxicity of the released compounds. Thus, these quaternaryammonium salt containing polymers are a class of biocidal polymers for avariety of microorganisms only by contact in the absence of diffusion ofany toxic substance.

In the case of polymeric quaternary ammonium salts, the polymers are farmore active than the corresponding monomers. Poly(trialkylvinylbenzylammonium chloride) and poly(N-benzyl-4-vinylpyridinium bromide) werefound to be more active than the corresponding monomers (J.Hazziza-Laskar et al. J. Appl. Polym. Sci. (1995) 58, 77-84). The higheractivity of the quaternary ammonium salt bearing polymers is due tolarger density of charges on the polymer making their interaction withcellular wall of microorganisms more efficient (G. Sauvet et al. J.Appl. Polym. Sci. (2000) 75, 1005-1012). It has been reported thatcrosslinked polyvinyl pyridinium halide captured bacterial cells byelectrostatic interaction but allowed the microorganisms to live.

A reactive silane developed by Dow Corning, DC 5700,(MeO)₃Si(CH₂)₃N⁺Me₂C₁₈H₃₇Cl reacted with many surfaces such as glass,cotton, polyester fibers or polyurethane foams. The materials treatedwith DC 5700 showed algicidal and bactericidal properties that aremaintained after repeated washings and no apparent leaching wasobserved. However, a vulcanized silicon elastomer obtained by reactingDC 5700 with polydimethylsiloxane (PDMS) terminated with —OH groups,exhibited leaching and its biocidal activity was lost upon subjectingthe elastomer to Soxhlet extraction.

There is a demand for insoluble antibacterial macromolecules. Suchpolymers could be utilized as sterilizers and packaging materials indrinking water and food applications (T Tashiro, Macromol. Mater. Eng.(2001), 286, 63-87). Quaternary ammonium salt derived disinfectants havebeen proposed to be suitable for preventing biomaterial centeredinfections. The biomaterials are functionalized with quaternary ammoniumsalts and since no antimicrobial agent is leached, long term protectionagainst bacterial colonization can be ensured. The antimicrobial effectsof soluble quaternary ammonium compounds increase with the length ofalkyl moieties on the N atom with the optimum chain length of 16-18carbon atoms (B. Gottenbos et al. Biomaterials, (2002), 23, 1417-1423).

All of the quaternary ammonium salts described above are non-functionalin the sense that they do not carry additional functional groups likehydroxyl (OH) which would be useful for making various polymers such aspolyethers, polyesters, or polyurethanes. Such modification would helpto render the quaternary ammonium salt bearing polymers insoluble inaqueous media, thereby avoiding issues such as leaching. Hence, polymersof this nature are perfect candidates for making surfaces active bycontact. Thus, when one attempts to synthesize such functionalizedquaternary ammonium salts, some of the factors to consider include: easeof producing such functionalized quaternary ammonium salts, ease ofavailability of starting materials in bulk quantities, toxicity of thereagents, stability of the starting materials, preserving the surfaceactivity by contact for prolonged periods, wide spectrum of activity,etc.

There have been two reports on the preparation of hydroxyl groupfunctionalized quaternary ammonium salts. J. Hazziza-Laskar et al., (J.Appl. Polym. Sci. (1993) 50, 651-662) reported the hydroxyl groupfunctionalized quaternary ammonium salts bearing siloxane pendantgroups. Quaternary ammonium salts were introduced as lateralsubstituents by chemical modification of a macromolecular polyol such ashydroxy telechelic polybutadiene. This reaction suffers from manydisadvantages such as isomerization, excess use of costly reagents,unreliable number of terminal functional groups, difficulties inpurification of polymers, presence of unwanted synthetic residues in thepolymers which leached upon immersing in water, thereby compromising theconcept of surface activity by contact, difficulty to remove unreactedbromide used for quaternization, isocyanates remaining in excess due touncertain hydroxyl functionalities because of which the films swelledrapidly and broke up in water, low concentration of quaternary ammoniumgroups, etc.

Thomas P. Klun et al. (J. Polym. Sci.: Part A: Polym. Chem. (1987))reported the preparation of tertiary amino secondary alcohols by thering opening of epoxides using carboxylic acids in the presence of toxicmetal salts like chromium (III) salts. There are many problemsassociated with this process, such as reversible reaction, elimination,thermal instability of quaternary ammonium salts, slow reaction, poorconversion, etc. More importantly, the tertiary amines obtained weremoderately high in molecular weight, in the range of above 1,000 toabout 6,000. Because of this high molecular weight nature of startingmaterial undergoing quaternization, quaternary ammonium salt formedremained inherently diluted, effectively reducing its antimicrobialactivity. Such quaternary ammonium salts are purposely built to beuseful as antistatic agents rather than disinfectants.

From the foregoing discussion, it is therefore clear that there remainsa need to provide for functional quaternary ammonium salts and theircorresponding polymers which can be prepared in a much simpler and highyield process, preferably from readily available starting materials by aone-step process. It is even more desirable to prepare multiplefunctional quaternary ammonium salts bearing more than one quaternaryammonium group.

SUMMARY

It is herein described the development of specialty polymers whichprotect surfaces immersed in sea against the settlement of marineorganisms. Specifically, dihydroxy functionalized quaternary ammoniumsalts were designed, synthesized and polymerized. These polymers werefound to exhibit very good antifouling characteristics. The developedpolymers completely prevented the settlement of tubeworms (one of thedominant fouling organisms in Singapore) over six weeks. The sampleslides immersed in sea were also free of growth of algae.

Advantageously, the application of the dihydroxy functionalizedquaternary ammonium salts bearing polymers is free of heavy metals andis a non-release based approach. Further, the polymers render surfacesactive by contact mechanism and activity can be established after mixingwith a commercial primer used in marine applications. The developedprocess has been further extended to photocuring and sol gel processes.

Thus, according to various embodiments, there is provided a quaternaryammonium halide of Formula (I)

-   -   wherein:    -   X is Br or Cl;    -   R is selected from the group consisting of C₁-C₂₀ alkyl, C₆-C₁₄        aryl, C₃-C₈ heteroaryl, C₃-C₂₀ cycloalkyl, and C₇-C₂₀ aralkyl;    -   R′ is selected from the group consisting of C₁-C₂₀ alkyl, C₃-C₂₀        cycloalkyl, C₇-C₂₀ aralkyl, and C₂-C₁₅ alkenyl.

According to various embodiments, there is provided a polymercomprising:

-   -   (A) a quaternary ammonium halide of Formula (I) linked through        urethane linkage; or

wherein R₁ is C₆-C₂₀ alkylcycloalkyl, preferably

-   -    n is any integer from 1 to 100; or

-   -    wherein R₁ is C₆-C₂₀ alkylcycloalkyl, preferably

-   -    n is any integer from 1 to 100; or    -   (D) a first quaternary ammonium halide of Formula (I) coupled to        a second quaternary ammonium halide of Formula (I) via a        urethane linkage, wherein the first quaternary ammonium halide        of Formula (I) is the same as or different from the second        quaternary ammonium halide of Formula (I); or    -   (E) a quaternary ammonium halide of Formula (I) coupled to a        quaternary ammonium halide of Formula (II) via a urethane        linkage,

-   -   wherein:    -   X is Br or Cl;    -   R is selected from the group consisting of C₁-C₂₀ alkyl, C₃-C₂₀        cycloalkyl, C₇-C₂₀ aralkyl, and C₂-C₁₅ alkenyl.

According to various embodiments, there is provided a method of making asurface antifouling, comprising coating the surface with a polymerdisclosed herein.

According to various embodiments, there is provided a method for makinga quaternary ammonium halide of Formula (I), comprising reacting atertiary amino primary alcohol with a dihaloaliphatic compound or adihaloaralkyl compound.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the sameparts throughout the different views. The drawings are not necessarilydrawn to scale, emphasis instead generally being placed uponillustrating the principles of various embodiments. In the followingdescription, various embodiments of the invention are described withreference to the following drawings.

FIG. 1 is a chart that shows settlement of barnacles on polyurethanesderived from diols bearing mono quaternary ammonium salt (after 2 weeks)(R1—glass coated with primer; Glass—uncoated glass).

FIG. 2 is a chart that shows settlement of tubeworms on polyurethanesderived from diols bearing mono quaternary ammonium salt (after 2weeks).

FIG. 3 is a chart that shows antifouling behavior of polyurethanesderived from diols bearing mono quaternary ammonium salt (after 2weeks).

FIG. 4 is a chart that shows antifouling behavior of physical blendspolyurethanes derived from diols bearing mono quaternary ammonium salts(after 4 weeks) (Base P—glass coated with film forming polymer;Glass—uncoated glass slide).

FIG. 5 is a chart that shows antifouling performance of polyurethanesderived from diols bearing two quaternary ammonium salts (after 2 weeks)(R2—glass coated with primer; Glass—uncoated glass slide).

FIG. 6 is a photograph that shows the appearance of coated glass slidesafter various periods of immersion. The glass slides are coated withselected polyurethanes derived from diols bearing two quaternaryammonium salts.

FIG. 7 is a photograph that shows the appearance of coated and uncoatedglass slides after 6 weeks of immersion. The glass slides are coatedwith selected polyurethanes derived from diols bearing two quaternaryammonium salts.

FIG. 8 shows various chemical structures of polyurethanes used in theexamples described herein.

DETAILED DESCRIPTION

The following detailed description refers to the accompanying drawingsthat show, by way of illustration, specific details and embodiments inwhich the invention may be practised. These embodiments are described insufficient detail to enable those skilled in the art to practise theinvention. Other embodiments may be utilized and structural, logical,and electrical changes may be made without departing from the scope ofthe invention. The various embodiments are not necessarily mutuallyexclusive, as some embodiments can be combined with one or more otherembodiments to form new embodiments.

According to various embodiments, there is disclosed a quaternaryammonium halide of Formula (I)

Formula (I) comprises two quaternary ammonium cations. In other words,the compound of Formula (I) is a diquaternary ammonium halide. Forbrevity and convenience sake, a quaternary ammonium halide is simplyreferred to in the present disclosure.

In Formula (I), X, at each occurrence, is a halide, such as F, Br or Cl.In other words, both X can be the same or different. In one embodiment,one X can be Br while the other X can be Cl. In another embodiment, bothX can be Br. In yet another embodiment, both X can be Cl. Othercombinations of suitable halides are also possible.

In various preferred embodiments, both X are Br or Cl.

In Formula (I), R, at each occurrence, is selected from the groupconsisting of C₁-C₂₀ alkyl, C₆-C₁₄ aryl, C₃-C₈ heteroaryl, C₃-C₂₀cycloalkyl, and C₇-C₂₀ aralkyl. In other words, both R can be the sameor different.

In Formula (I), R′ is selected from the group consisting of C₁-C₂₀alkyl, C₃-C₂₀ cycloalkyl, C₇-C₂₀ aralkyl, and C₂-C₁₅ alkenyl.

The term “aliphatic”, alone or in combination, refers to a straightchain or branched chain hydrocarbon comprising at least one carbon atom.Aliphatics include alkyls, alkenyls, and alkynyls. In certainembodiments, aliphatics are optionally substituted, i.e. substituted orunsubstituted. Aliphatics include, but are not limited to, methyl,ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl, pentyl, hexyl,ethenyl, propenyl, butenyl, ethynyl, butynyl, propynyl, and the like,each of which may be optionally substituted. As used herein, aliphaticis not intended to include cyclic groups.

The term “alkyl”, alone or in combination, refers to a fully saturatedaliphatic hydrocarbon. In certain embodiments, alkyls are optionallysubstituted. In certain embodiments, an alkyl comprises 1 to 20 carbonatoms, for example 1 to 10 carbon atoms, wherein (whenever it appearsherein in any of the definitions given below) a numerical range, such as“1 to 20” or “C₁-C₂₀”, refers to each integer in the given range, e.g.“C₁-C₂₀ alkyl” means an alkyl group comprising 1 carbon atom, 2, 3, 4,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbonatoms. Examples of alkyl groups include, but are not limited to, methyl,ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl,tert-amyl, pentyl, hexyl, heptyl, octyl and the like.

The term “alkenyl”, alone or in combination, refers to an aliphatichydrocarbon having one or more carbon-carbon double-bonds, such as twoor three carbon-carbon double-bonds. In certain embodiments, alkenylsare optionally substituted, i.e. substituted or unsubstituted. Incertain embodiments, an alkenyl comprises 2 to 15 carbon atoms. “C₂-C₁₅alkenyl” means an alkenyl group comprising 2, 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, or 15 carbon atoms. Examples of alkenyls include, butare not limited to, ethenyl, propenyl, butenyl, 1,4-butadienyl,pentenyl, hexenyl, 4-methylhex-1-enyl, 4-ethyl-2-methylhex-1-enyl andthe like.

The term “cyclo”, “cyclic” or “carbocycle” refers to a group comprisinga covalently closed ring, wherein each of the atoms forming the ring isa carbon atom. A cyclic ring may be formed by 3, 4, 5, 6, 7, 8, 9, 10,11, 12, 13, 14, 15, 16, 17, 18, 19 or 20 carbon atoms. Carbocycles maybe optionally substituted. Accordingly, a C₃-C₂₀ cycloalkyl is a C₃-C₂₀alkyl except that the alkyl group is not aliphatic but cyclic. Examplesof cycloalkyl groups include, but are not limited to, cyclopropane,cyclobutane, cyclopentane, cyclohexane and the like.

The term “aromatic” refers to a group comprising a covalently closedplanar ring having a delocalized π-electron system comprising 4n+2 πelectrons, where n is an integer. Aromatic rings may be formed by 5, 6,7, 8, 9 or more atoms. Aromatics may be optionally substituted. Examplesof aromatic groups include, but are not limited to phenyl, naphthalenyl,phenanthrenyl, anthracenyl, tetralinyl, fluorenyl, indenyl, and indanyl.The term aromatic includes, for example, benzenoid groups, connected viaone of the ring-forming carbon atoms, and optionally carrying one ormore substituents selected from an aryl, a heteroaryl, a cycloalkyl, anon-aromatic heterocycle, a halo, a hydroxy, an amino, a cyano, a nitro,an alkylamido, an acyl, a C₁-C₆ alkoxy, a C₁-C₆ alkyl, a C₁-C₆hydroxyalkyl, a C₁-C₆ aminoalkyl, an alkylsulfenyl, an alkylsulfinyl, analkylsulfonyl, an sulfamoyl, or a trifluoromethyl. In certainembodiments, an aromatic group is substituted at one or more of thepara, meta, and/or ortho positions. Examples of aromatic groupscomprising substitutions include, but are not limited to, phenyl,3-halophenyl, 4-halophenyl, 3-hydroxyphenyl, 4-hydroxyphenyl,3-aminophenyl, 4-aminophenyl, 3-methylphenyl, 4-methylphenyl,3-methoxyphenyl, 4-methoxyphenyl, 4-trifluoromethoxyphenyl,3-cyanophenyl, 4-cyanophenyl, dimethylphenyl, naphthyl, hydroxynaphthyl,hydroxymethylphenyl, (trifluoromethyl)phenyl, alkoxyphenyl,4-morpholin-4-ylphenyl, 4-pyrrolidin-1-ylphenyl, 4-pyrazolylphenyl,4-triazolylphenyl, and 4-(2-oxopyrrolidin-1-yl)phenyl.

The term “aryl” refers to an aromatic ring wherein each of the atomsforming the ring is a carbon atom. Aryl rings may be formed by 5, 6, 7,8, 9 or more carbon atoms. Aryl groups may be optionally substituted. Incertain embodiments, aryls are optionally substituted, i.e. substitutedor unsubstituted. In certain embodiments, an aryl comprises 6 to 14carbon atoms. “C₆-C₁₄ aryl” means an aryl group comprising 6, 7, 8, 9,10, 11, 12, 13, or 14 carbon atoms. Accordingly, “C₇-C₂₀ aralkyl” meansan aryl group bound to an alkyl group. Examples of aralkyls include, butare not limited to, 3-methylphenyl, 4-methylphenyl, dimethylphenyl andthe like.

The term “heteroaryl” refers to an aromatic heterocycle. Heteroarylrings may be formed by four, five, six, seven, eight, nine, or more thannine atoms. Heteroaryls may be optionally substituted. Examples ofheteroaryl groups include, but are not limited to, aromatic C₃-C₈heterocyclic groups comprising one oxygen or sulfur atom or up to fournitrogen atoms, or a combination of one oxygen or sulfur atom and up totwo nitrogen atoms, and their substituted as well as benzo- andpyrido-fused derivatives, for example, connected via one of thering-forming carbon atoms. In certain embodiments, heteroaryl groups areoptionally substituted with one or more substituents, independentlyselected from halo, hydroxy, amino, cyano, nitro, alkylamido, acyl,C₁-C₆-alkoxy, C₁-C₆-alkyl, C₁-C₆-hydroxyalkyl, C₁-C₆-aminoallcyl,alkylsulfenyl, alkylsulfinyl, alkylsulfonyl, sulfamoyl, ortrifluoromethyl. Examples of heteroaryl groups include, but are notlimited to, unsubstituted and mono- or di-substituted derivatives offuran, benzofuran, thiophene, benzothiophene, pyrrole, pyridine, indole,oxazole, benzoxazole, isoxazole, benzisoxazole, thiazole, benzothiazole,isothiazole, imidazole, benzimidazole, pyrazole, indazole, tetrazole,quinoline, isoquinoline, pyridazine, pyrimidine, purine and pyrazine,furazan, 1,2,3-oxadiazole, 1,2,3-thiadiazole, 1,2,4-thiadiazole,triazole, benzotriazole, pteridine, phenoxazole, oxadiazole,benzopyrazole, quinolizine, cinnoline, phthalazine, quinazoline, andquinoxaline.

The term “optionally substituted” or “substituted or unsubstituted”refers to a group in which none, one, or more than one of the hydrogenatoms have been replaced with one or more groups such as, but are notlimited to, alkyl, heteroalkyl, haloalkyl, heterohaloalkyl, cycloalkyl,aryl, arylalkyl, heteroaryl, non-aromatic heterocycle, hydroxy, alkoxy,aryloxy, mercapto, alkylthio, arylthio, cyano, halo, carbonyl,thiocarbonyl, O-carbamyl, N-carbamyl, O-thiocarbamyl, N-thiocarbamyl,C-amido, N-amido, S-sulfonamido, N-sulfonamido, C-carboxy, O-carboxy,isocyanato, thiocyanato, isothiocyanato, nitro, silyl,trihalomethanesulfonyl, and amino, including mono- and di-substitutedamino groups. In embodiments in which two or more hydrogen atoms havebeen substituted, the substituent groups may be linked to form a ring.

The term “heteroatom” refers to an atom other than carbon or hydrogen.Heteroatoms are typically independently selected from oxygen, sulfur,nitrogen, and phosphorus, but are not limited to those atoms. Inembodiments in which two or more heteroatoms are present, the two ormore heteroatoms may all be the same as one another, or some or all ofthe two or more heteroatoms may each be different from the others.

According to various preferred embodiments, in Formula (I) R′ comprisesa C₁-C₂₀ alkyl, and more preferably a C₁-C₁₀ alkyl.

In certain preferred embodiments, in Formula (I) R′ is

In alternative various preferred embodiments, in Formula (I) R′comprises a C₇-C₂₀ aralkyl, and more preferably a C₇-C₁₀ aralkyl.

In certain various preferred embodiments, in Formula (I) R′ is

In various preferred embodiments, in Formula (I) R, at each occurrence,comprises a C₁-C₂₀ alkyl, and more preferably a C₁-C₁₀ alkyl.

According to one preferred embodiment, in Formula (I) R, at eachoccurrence, is

A method for making the quaternary ammonium halide of Formula (I)according to various embodiments is next described. The method comprisesreacting a tertiary amino primary alcohol with a dihaloaliphaticcompound or a dihaloaralkyl compound.

In one embodiment, the tertiary amino primary alcohol may be

In various embodiments, the dihaloaliphatic compound may be1,2-dichloroethane, 1,3-dichloropropane, 1,4-dichlorobutane,1,5-dichloropentane, 1,6-dichlorohexane, 1,7-dichloroheptane,1,8-dichlorooctane, 1,9-dichlorononane, 1,10-dichlorodecane,1,2-dibromoethane, 1,3-dibromopropane, 1,4-dibromobutane,1,5-dibromopentane, 1,6-dibromohexane, 1,7-dibromoheptane,1,8-dibromooctane, 1,9-dibromononane, 1,10-dibromodecane.

In various embodiments, the dihaloaralkyl compound may be

or a regioisomer thereof.

According to various embodiments, the tertiary amino primary alcoholcomprises N—N-dimethyl aminoethanol.

According to various embodiments, the dihaloaliphatic compound comprises1,10-dichlorodecane.

According to various embodiments, the dihaloaralkyl compound comprisesα,α′-dibromo-m-xylene.

As mentioned in earlier paragraphs, the disclosed quaternary ammoniumhalides of Formula (I) is rendered functional (e.g. in terms ofsolubility in aqueous media) by virtue of the two terminal hydroxyl(—OH) groups. The inventor has surprisingly found that such functionalquaternary ammonium halides can be extended to form polymers and forusing in other techniques such as UV curing and sol-gel processes. Thequaternary ammonium halides of Formula (I) and their correspondingpolymers find particular use in preventing settlement of micro- andmacro-organisms on a surface. Advantageously, the quaternary ammoniumhalides of Formula (I) and their corresponding polymers are free ofheavy metals and the mechanism of antifouling action is not based onleaching.

Thus, according to various embodiments, there is provided a polymercomprising:

(A) a quaternary ammonium halide of Formula (I) linked through urethanelinkage; or

wherein R₁ is C₆-C₂₀ alkylcycloalkyl, preferably

n is any integer from 1 to 100; or

wherein R₁ is C₆-C₂₀ alkylcycloalkyl, preferably

n is any integer from 1 to 100; or (D) a first quaternary ammoniumhalide of Formula (I) coupled to a second quaternary ammonium halide ofFormula (I) via a urethane linkage, wherein the first quaternaryammonium halide of Formula (I) is the same as or different from thesecond quaternary ammonium halide of Formula (I); or(E) a quaternary ammonium halide of Formula (I) coupled to a quaternaryammonium halide of Formula (II) via a urethane linkage,

wherein:

X is Br or Cl;

R is selected from the group consisting of C₁-C₂₀ alkyl, C₃-C₂₀cycloalkyl, C₇-C₂₀ aralkyl, and C₂-C₁₅ alkenyl.

In various embodiments, n may be any integer from 10 to 50.

In various preferred embodiments, the polymer is:

wherein R₁ is C₆-C₂₀ alkylcycloalkyl, preferably

In yet other various preferred embodiments, the polymer is one of:

wherein R₁ is C₆-C₂₀ alkylcycloalkyl, preferably

As mentioned earlier, a surface may be made antifouling by coating thesurface with a polymer disclosed herein (i.e. an active by contactsurface is obtained). Various coating techniques may be used to coat ordeposit a layer of the polymer onto the surface. In one example, thepolymer may be coated with the use of doctor blade. Another technique ofcoating includes spin coating a solution of the polymer onto the surfaceand allowing the polymer to develop.

In cases where the surface to be protected forms part of a marinevessel, for example, it is preferred that prior to coating the surface,the polymer is first blended with a primer used in marine coatings. Anexample of a commercial primer used in marine coatings may be Primacon.

The presently disclosed quaternary ammonium halide bearing polymers mayalso find use in photocuring processes. As an example, the polymers (oroligomers) terminated with hydroxyl groups can be used to link withisocyanate bearing methacrylates and simultaneously cured by UV light ormodified to terminate with (meth)acrylates and cured with other vinylmonomers by UV light.

A further use of the presently disclosed quaternary ammonium saltbearing polymers may lie in sol-gel processes. As an example, thepolymers (or its oligomers) terminated with hydroxyl groups can becondensed with tetraalkoxy silanes (or derivatives thereof),tetraacetoxy silanes (or derivatives thereof), or isocyanate bearingtriethoxy silanes in a sol-gel process.

In order that the invention may be readily understood and put intopractical effect, particular embodiments will now be described by way ofthe following non-limiting examples.

Examples

Preparation of Functional Quaternary Ammonium Salts and AntifoulingEvaluation in the Sea

An attempt was made to find out the efficacy of various structuralmotifs, namely, four alkyl and aralkyl halides were chosen to makequaternary ammonium salts viz. benzyl bromide, benzyl chloride, dodecylbromide and dodecyl chloride.

Hydroxyl group functionalized diol monomers were prepared from thesealkyl and aralkyl halides as shown in Scheme 1.

Polyurethanes were prepared from the quaternary ammonium salt bearingdiols as shown in Scheme 2.

In addition to these homo polyurethanes, some copolyurethanes were alsoprepared and evaluated. The preparation of copolyurethanes is shown inScheme 3.

These polyurethanes were dissolved in methanol to make 50 wt % polymersolution. The polymer solution was then mixed with a commercialantifouling primer like Primacon and coated on frosted glass slides (7cm long, 2.5 cm wide). Each polymer solution mixed with primer wascoated with the help of an applicator on five such glass slides placedparallel to each other and allowed to dry under ambient conditions in afume hood. After drying for a week, the glass slides were subjected toleachate test, followed by immersion in sea. Among the quaternaryammonium salt bearing polyurethanes, those copolyurethanes derived frombenzyl bromide and dodcecyl chloride showed some antifouling activity ascompared to the blank glass slide and the slide coated with primer aloneas shown in FIGS. 1, 2 and 3. However, the antifouling activity observedafter two weeks of exposure in sea was far from desirable. It is alsointeresting to note that they acted in a unique way, e.g.copolyurethanes bearing quaternary ammonium salt derived from dodecylchloride was active against barnacles and that of benzyl bromide wasactive against tubeworms. In general, the copolyurethanes showed betterantifouling activity than the homo polyurethanes.

In order to see the effect of physical blend of homo polyurethanesderived from dodecyl chloride and benzyl bromide, a 1:1 mixture of thesepolymers were dissolved in methanol. The methanol solution was thenmixed with a film forming polymer and coated on a glass slide. The glassslide was then evaluated in the same manner as that of primer blendedpolyurethanes. After 4 weeks of exposure in sea water, the physicalblend exhibited superior antifouling performance as compared to that ofthe respective homo polyurethanes as well as blank and base polymer asshown in FIG. 4. However, still the antifouling performance is wellbelow the desired level.

Since the antifouling activity of mono quaternary ammonium salt bearinghomo and copolyurethanes was somewhat inadequate, diols bearing twoquaternary ammonium salt groups were designed and synthesized as shownin Scheme 4. Homo and copolyurethanes were prepared from diols bearingtwo quaternary ammonium salts (Schemes 5 and 6, respectively). Among thevarious combinations studied this class of polymers showed superiorantifouling properties which is highly desired since the performance isequal or nearly comparable to that of biocide based antifoulingsolutions. Because of the non-leaching, active by contact nature,antifouling surfaces formed by these polymers are highly preferred. Theantifouling behavior of selected polyurethanes derived from diolsbearing two quaternary ammonium salts is shown in FIG. 5. As can benoted from the figure, even though the exposure is only for two weeks,the fouling pressure was very high can be noted from the blank glassslide as well as that coated with the primer. Photographs (FIGS. 6 and7) of the slides coated with selected polyurethanes derived from diolsbearing two quaternary ammonium salts also revealed that these werecompletely free of tube worms. Tubeworms are one of the foulingorganisms abundantly present in the waters surrounding Singapore and arealso active throughout the year. A closer look at the nature of barnaclesettlement at the reference slides clearly indicate that these organismssettled at very early stage of immersion and were abundant. A comparisonbetween the reference slides and that of those coated with selectedpolyurethanes derived from diols bearing two quaternary ammonium saltsclearly point to the superior performance in terms of not only hardfouling but also against soft fouling.

Details on Matrix Assisted Laser Desorption and Ionization (MALDI)Characterization

Matrix Assisted Laser Desorption and Ionization Time-of-Flight-MassSpectroscopy (MALDI-ToF MS) analyses of polymers were carried out usingBruker Autoflex speed system with 2,5-dihydroxybenzoic acid matrix withsilver trifluoroacetate cationization agent. The matrix was dissolved inmethanol at 10 mg/mL concentration. The sample and cationzation agentprepared at 2.0 mg/mL concentration and mixed 10:1:1 ratios. Eachspectra were collected approximately 5000 laser shots on linear modeeither positive or negative technique. The molecular weight andmolecular weight distribution of copolymer samples were calculated usingPolymerix software.

Preparation of Diol Monomers Bearing One Quaternary Ammonium Salt

N,N-Bis(2-hydroxyethyl)-N-methyl dodecyl ammonium bromide (DEA-BDD)

N-methyldiethanolamine (4.9686 g, 0.042 mol) was added to a single neckround bottom flask. The flask was then fitted with a drying tube andstirred using a magnetic stirrer. Bromododecane (10 mL, 0.042 mol) wasadded slowly through a syringe to control the exothermic mixing. Aftercompleting the addition the reaction mixture was stirred under ambientconditions for 30 minutes. It was then immersed in a preheated oil bathmaintained at 80° C. The contents of the flask became viscous and thestirring stopped after 4 h. A waxy solid was obtained upon cooling toroom temperature. Yield: 14 g. ¹H-NMR analysis of the product indicatedthat the —CH₃ group attached to the N atom shifted from 2.2 ppm in thestarting material to 3.3 ppm upon quaternization. The methylene groupattached to the N atom also shifted to 3.8 ppm.

N,N-Bis(2-hydroxyethyl)-N-methyl dodecyl ammonium chloride (DEA-CDD)

N-methyldiethanolamine (5.0096 g, 0.042 mol) was added to a single neckround bottom flask. The flask was then fitted with a drying tube andstirred using a magnetic stirrer. Chlorododecane (10 mL, 0.043 mol) wasadded slowly through a syringe to control the exothermic mixing. Aftercompleting the addition the reaction mixture was stirred under ambientconditions for 30 minutes. It was then immersed in a preheated oil bathmaintained at 100° C. After 42 h the two immiscible phases turned into asingle phase. A waxy solid was obtained upon cooling to roomtemperature. Yield: 12 g. ¹H-NMR analysis indicated that the —CH₃ groupattached to the N atom shifted from 2.2 ppm in the starting material to3.3 ppm after quaternization.

N,N-Bis(2-hydroxyethyl)-N-methyl benzyl ammonium bromide (DEA-BzBr)

N-methyldiethanolamine (10.0293 g, 0.084 mol) was added to a single neckround bottom flask. The flask was then fitted with a drying tube andstirred using a magnetic stirrer. Benzyl bromide (10 mL, 0.084 mol) wasadded very slowly through a syringe to control the exothermic mixing.After completing the addition the reaction mixture was stirred underambient conditions and it turned highly viscous within few minutes andsolidified. The solidified reaction mixture was kept under ambientconditions overnight. The solid was soaked in dry dichloromethane (50mL). The solid was broken with the help of spatula, transferred to asample bottle and dried in a vacuum oven. Yield: 23 g. 41-NMR analysisindicated that the —CH₃ group attached to the N atom shifted from 2.2ppm in the starting material to 3.1 ppm upon quaternization.

N,N-Bis(2-hydroxyethyl)-N-methyl benzyl ammonium chloride (DEA-BzCl)

N-methyldiethanolamine (10.4124 g, 0.087 mol) was added to a single neckround bottom flask. The flask was then fitted with a drying tube andstirred using a magnetic stirrer. Benzyl chloride (10 mL, 0.087 mol) wasadded very slowly through a syringe to control the exothermic mixing.After completing the addition the reaction mixture was stirred underambient conditions overnight. The contents of the flask solidifiedduring this period. The solid was soaked in dry dichloromethane (50 mL).Then the solid was broken with the help of spatula, transferred to asample bottle and dried in a vacuum oven. Yield: 20 g. 41-NMR analysisindicated that the —CH₃ group attached to the N atom shifted from 2.2ppm in the starting material to 3.2 ppm after quaternization.

Preparation of Diol Monomers Bearing Two Quaternary Ammonium Salts

Reaction product of N,N-dimethylaminoethanol and 1,10-dichlorodecane(AE-DCD)

N,N-dimethylaminoethanol (4.216 g, 0.047 mol) was added to a single neckround bottom flask. The flask was then fitted with a drying tube andstirred using a magnetic stirrer. 1,10-dichlorodecane (5 mL, 0.024 mol)was added slowly through a syringe to control the exothermic mixing.After completing the addition the reaction mixture was stirred underambient conditions for 30 minutes. It was then immersed in a preheatedoil bath maintained at 80° C. The contents of the flask solidified afterheating for 4 h. The solid was washed with diethyl ether and dried in avacuum oven. Yield: 6 g. ¹-NMR analysis indicated that the —CH₃ groupattached to the N atom shifted to 3.3 ppm after quaternization.

Reaction product of N,N-dimethylaminoethanol and 1,4-dichlorobutane(AE-DCB)

N,N-dimethylaminoethanol (16.284 g, 0.2 mol) was added to a single neckround bottom flask. The flask was then fitted with a drying tube andstirred using a magnetic stirrer. 1,4-dichlorobutane (10 mL, 0.1 mol)was added slowly through a syringe to control the exothermic mixing.After completing the addition the reaction mixture was stirred underambient conditions overnight. ¹-NMR analysis of the reaction mixtureindicated that no reaction occurred. It was then immersed in a preheatedoil bath maintained at 80° C. The contents of the flask solidifiedwithin 30 minutes. The flask was cooled and the solid was washed withdiethyl ether and dried in a vacuum oven. Yield: 20 g. ¹-NMR analysisindicated that the —CH₃ group attached to the N atom shifted to 3.1 ppmafter quaternization.

Reaction product of N,N-dimethylaminoethanol and α,α′-dibromo-m-xylene(AE-mX)

α,α′-dibromo-m-xylene (7.8887 g, 0.03 mol) was dissolved in drydichloromethane (40 mL) in single neck round bottom flask. The flask wasthen fitted with a drying tube. N,N-dimethylaminoethanol (5.316 g, 0.06mol) was added slowly through a syringe to control the exothermicreaction. The reaction mixture immediately turned milky and a separateliquid layer was formed. The reaction mixture was stirred under ambientconditions for 24 h. Dichloromethane was decanted off. The residue waswashed with dichloromethane (2×25 mL) and dried in a rotavapor. Yield:10 g. ¹H-NMR analysis indicated that the —CH₃ group attached to the Natom shifted to 3.3 ppm upon quaternization.

Reaction product of N,N-dimethylaminoethanol and α,α′-dibromo-p-xylene(AE-pX)

α,α′-dibromo-m-xylene (7.8778 g, 0.03 mol) was dissolved in drydichloromethane (80 mL) in single neck round bottom flask. The flask wasthen fitted with a drying tube. N,N-dimethylaminoethanol (5.316 g, 0.06mol) was added slowly through a syringe to control the exothermicreaction. The reaction mixture immediately turned milky and afterwards awhite solid separated from the reaction mixture. The reaction mixturewas stirred under ambient conditions for 24 h. Dichloromethane wasdecanted off. The residue was washed with dichloromethane (2×25 mL) anddried in a rotavapor. Yield: 12 g. The product was insoluble in organicsolvents as well as in water.

Preparation of Homopolyurethanes

Preparation of P1

DEA-BzBr (2.3611 g, 0.008 mol) was dissolved in dry N,N-dimethylformamide (20 mL) in a single neck flask fitted with a drying tube at80° C. After completely dissolving the solid, dibutyl tin dilaurate (3drops) was added followed by bis(4-isocyanatocyclohexyl)methane (2 mL,0.008 mol). The reaction mixture was heated and stirred at 80° C. for 24h. Then the flask was cooled and the light brown solution was added dropwise into large excess of ethyl acetate (300 mL), stirred well andallowed to settle. The solvent mixture was decanted off, washed againwith ethyl acetate (2×25 mL) and dried in a vacuum oven. Yield: 4 g.

Preparation of P3

DEA-CDD (2.682 g, 0.008 mol) was dissolved in dry tetrahydrofuran (25mL) in a single neck flask fitted with a reflux condenser and a dryingtube. After completely dissolving the solid, dibutyl tin dilaurate (3drops) was added followed by bis(4-isocyanatocyclohexyl)methane (2 mL,0.008 mol). The reaction mixture was refluxed for 24 h. Then the flaskwas cooled and the solvent was removed in a rotavapor. The residue waswashed with diethyl ether (3×25 mL) and then dried in a vacuum oven.Yield: 4.2 g.

Preparation of AE-DCD-U

AE-DCD (8.2293 g, 0.02 mol) was heated in dry N,N-dimethyl formamide (70mL) in a single neck flask fitted with a drying tube at 80° C. to form awhite dispersion for 15 minutes. Then dibutyl tin dilaurate (0.1634 g,0.0003 mol) was added followed by bis(4-isocyanatocyclohexyl)methane (5mL, 0.02 mol). The reaction mixture was heated and stirred at 80° C. for30 h. Then the flask was cooled and the light brown solution was addeddrop wise into large excess of ethyl acetate (800 mL), stirred well andallowed to settle. The solvent mixture was decanted off, washed againwith ethyl acetate (2×50 mL) and dried in a vacuum oven. Yield: 11 g.

Preparation of AE-mX-U

AE-mX (7.2522 g, 0.02 mol) was heated in dry N,N-dimethyl formamide (60mL) in a single neck flask fitted with a drying tube at 80° C. to form aclear solution. Then dibutyl tin dilaurate (0.1591 g, 0.0003 mol) wasadded followed by bis(4-isocyanatocyclohexyl)methane (5 mL, 0.02 mol).The reaction mixture was heated and stirred at 80° C. for 30 h. Then theflask was cooled and the light brown solution was added drop wise intolarge excess of ethyl acetate (800 mL), stirred well and allowed tosettle. The solvent mixture was decanted off, washed again with ethylacetate (2×50 mL) and dried in a vacuum oven. Yield: 10 g.

Preparation of Copolyurethanes

Preparation of P2

DEA-BzBr (2.0078 g, 0.007 mol), polyethylene glycol (MW 600) (1.715 g,0.003 mol), and bishydroxy terminated polydimethyl siloxane (MW 5600)(1.976 g, 0.0004 mol) were dissolved in dry N,N-dimethyl formamide (25mL) in a single neck flask fitted with a drying tube at 80° C. Afterforming a hazy solution, dibutyl tin dilaurate (3 drops) was addedfollowed by bis(4-isocyanatocyclohexyl)methane (2.5 mL, 0.01 mol). Thereaction mixture was heated and stirred at 80° C. for 24 h. Then theflask was cooled and the light brown solution was added drop wise intolarge excess of ethyl acetate (300 mL), stirred well and allowed tosettle. The solvent mixture was decanted off, residue washed again withethyl acetate (2×25 mL) and dried in a vacuum oven. Yield: 6 g.

Preparation of P4

DEA-CDD (2.0469 g, 0.006 mol), polyethylene glycol (MW 600) (1.5553 g,0.003 mol), and bishydroxy terminated polydimethyl siloxane (MW 5600)(1.8456 g, 0.0003 mol) were dissolved dry tetrahydrofuran (30 mL). Afterforming a hazy solution, dibutyl tin dilaurate (3 drops) was addedfollowed by bis(4-isocyanatocyclohexyl)methane (2.2 mL, 0.01 mol). Thereaction mixture was refluxed for 24 h. Then the flask was cooled andthe solvent was removed in a rotavapor. The residue was washed withdiethyl ether (3×25 mL) and then dried in a vacuum oven. Yield: 6.5 g.

Preparation of Polyurethanes from Mixed Monomers

Preparation of P5

AE-DCD (4.1156 g, 0.01 mol) and AE-mX (3.6702 g, 0.01 mol) were heatedin dry N,N-dimethyl formamide (60 mL) in a single neck flask fitted witha drying tube at 80° C. for 15 minutes. Then dibutyl tin dilaurate(0.1692 g, 0.0003 mol) was added followed bybis(4-isocyanatocyclohexyl)methane (5.1 mL, 0.02 mol). The reactionmixture was heated and stirred at 80° C. for 30 h. Then the flask wascooled and the light brown solution was added drop wise into largeexcess of ethyl acetate (800 mL), stirred well and allowed to settle.The solvent mixture was decanted off, washed again with ethyl acetate(2×50 mL) and dried in a vacuum oven. Yield: 11 g. Molecular weight (asdetermined by MALDI): M_(n)=6060 M_(w)=7860 PD=1.3.

Preparation of P6

AE-DCD (1.2907 g, 0.003 mol) and DEA-BzBr (1.1823 g, 0.004 mol) wereheated in dry N,N-dimethyl formamide (20 mL) in a single neck flaskfitted with a drying tube at 80° C. until DEA-BzBr dissolved completely.Then dibutyl tin dilaurate (3 drops) was added followed bybis(4-isocyanatocyclohexyl)methane (1.7 mL, 0.007 mol). The reactionmixture was heated and stirred at 80° C. for 30 h. Then the flask wascooled and the light brown solution was added drop wise into largeexcess of ethyl acetate (300 mL), stirred well and allowed to settle.The solvent mixture was decanted off, washed again with ethyl acetate(2×25 mL) and dried in a vacuum oven. Yield: 3.8 g. Molecular weight (asdetermined by MALDI): M_(n)=4130 M_(w)=5600 PD=1.4.

Preparation of P7

DEA-CDD (1.0125 g, 0.003 mol) and AE-mX (1.1509 g, 0.003 mol) wereheated in dry N,N-dimethyl formamide (20 mL) in a single neck flaskfitted with a drying tube at 80° C. to form a clear solution. Thendibutyl tin dilaurate (3 drops) was added followed bybis(4-isocyanatocyclohexyl)methane (1.5 mL, 0.006 mol). The reactionmixture was heated and stirred at 80° C. for 24 h. Then the flask wascooled and the light brown solution was added drop wise into largeexcess of ethyl acetate (300 mL), stirred well and allowed to settle.The solvent mixture was decanted off, washed again with ethyl acetate(2×25 mL) and dried in a vacuum oven. Yield: 3 g.

Preparation of P8

DEA-CDD (1.1104 g, 0.003 mol) and AE-DCD (1.3064 g, 0.003 mol) wereheated in dry N,N-dimethyl formamide (20 mL) in a single neck flaskfitted with a drying tube at 80° C. for 15 minutes. Then dibutyl tindilaurate (4 drops) was added followed bybis(4-isocyanatocyclohexyl)methane (1.6 mL, 0.006 mol). The reactionmixture was heated and stirred at 80° C. for 24 h. Then the flask wascooled and the light brown solution was added drop wise into largeexcess of ethyl acetate (300 mL), stirred well and allowed to settle.The solvent mixture was decanted off, washed again with ethyl acetate(2×25 mL) and dried in a vacuum oven. Yield: 3.5 g. Molecular weight (asdetermined by MALDI): M_(n)=5400 M_(w)=7500 PD=1.4.

UV Curing of Polyurethanes

Step 1—Preparation of Polyurethane Diol Macromer

AE-DCD (0.8746 g, 0.0023 mol) and AE-mX (1.0421 g, 0.0024 mol) wereheated in dry N,N-dimethyl formamide (10 mL) in a single neck flaskfitted with a drying tube at 80° C. for 15 minutes. Then dibutyl tindilaurate (0.0956 g, 0.0002 mol) was added followed bybis(4-isocyanatocyclohexyl)methane (1 mL, 0.004 mol). The reactionmixture was heated and stirred at 80° C. for 24 h.

Step 2—Reactive Curing Under UV Light

Photoinitiator, 2,2-dimethoxy-1,2-dipheny ethan-1-one (0.01 g, 0.00004mol) was added to the macromer solution of step 1 at room temperatureand stirred well. Methyl methacrylate (0.468 g, 0.005 mol) was thenadded and stirred. This solution was then transferred to a petri dish.Isocyanatoethyl methacrylate (0.66 g, 0.004 mol) was added throughoutthe macromer solution in the petri dish and exposed to UV light for 2 h.Then the dish was taken out and the supernatant liquid was collected ina beaker. The petri dish was treated with dichloromethane followed bymethanol and allowed to dry under ambient conditions to yield a paleyellow solid, broken film. Yield: 1.83 g (45%). The solution collectedfrom the petri dish yielded 1.4783 g (50%) of solid after precipitationin ethyl acetate followed by drying in vacuum oven.

Preparation of Sol-Gel Coating Using Polyurethanes

Step 1—Preparation of Polyurethane Diol Macromer

AE-DCD (0.9083 g, 0.0023 mol) and AE-mX (1.0368 g, 0.0023 mol) wereheated in dry N,N-dimethyl formamide (10 mL) in a single neck flaskfitted with a drying tube at 80° C. for 15 minutes. Then dibutyl tindilaurate (0.092 g, 0.0002 mol) was added followed bybis(4-isocyanatocyclohexyl)methane (1 mL, 0.004 mol). The reactionmixture was heated and stirred at 80° C. for 24 h. Then the reactionsolution was cooled down to room temperature. Triethoxysilylpropylisocyanate (0.999 g, 0.004 mol) was added and stirred overnightunder ambient conditions.

Step 2—Gelation

The macromer solution of step 1 was transferred to a 100 mL beaker.

Hydroxy terminated polydimethyl siloxane (MW 4670) (14.2425 g, 0.003mol) was added followed by tetrabutylammonium fluoride solution (1 mMsolution in tetrahydrofuran) (0.5 mL) and stirred well. The beaker wassubsequently immersed in an oil bath and heated at 60° C. for 24 h. Thebeaker was then cooled, washed with dichloromethane followed by methanoland dried in a vacuum oven. Yield: 6.3117 g.

Coating of Frosted Glass Slides of 7 cm×2 cm

About 1 g of polymer was dissolved in 2 mL of methanol. To this solution8 mL of Primacon (commercial primer for underwater coatings) was addedand stirred well. This mixture was coated on five frosted glass plateswith the help of doctor blade and allowed to develop under ambientconditions. After 1 week, the glass slides were subjected to leachatetest followed by immersion in sea. Two sets of references were used, oneuncoated glass slides and the other coated with Primacon alone. Theimmersed glass slides were subjected to photogrid analysis afterexposure for periods of two weeks or above.

By “comprising” it is meant including, but not limited to, whateverfollows the word “comprising”. Thus, use of the term “comprising”indicates that the listed elements are required or mandatory, but thatother elements are optional and may or may not be present.

By “consisting of” is meant including, and limited to, whatever followsthe phrase “consisting of”. Thus, the phrase “consisting of” indicatesthat the listed elements are required or mandatory, and that no otherelements may be present.

The inventions illustratively described herein may suitably be practicedin the absence of any element or elements, limitation or limitations,not specifically disclosed herein. Thus, for example, the terms“comprising”, “including”, “containing”, etc. shall be read expansivelyand without limitation. Additionally, the terms and expressions employedherein have been used as terms of description and not of limitation, andthere is no intention in the use of such terms and expressions ofexcluding any equivalents of the features shown and described orportions thereof, but it is recognized that various modifications arepossible within the scope of the invention claimed. Thus, it should beunderstood that although the present invention has been specificallydisclosed by preferred embodiments and optional features, modificationand variation of the inventions embodied therein herein disclosed may beresorted to by those skilled in the art, and that such modifications andvariations are considered to be within the scope of this invention.

By “about” in relation to a given numerical value, such as fortemperature and period of time, it is meant to include numerical valueswithin 10% of the specified value.

The invention has been described broadly and generically herein. Each ofthe narrower species and sub-generic groupings falling within thegeneric disclosure also form part of the invention. This includes thegeneric description of the invention with a proviso or negativelimitation removing any subject matter from the genus, regardless ofwhether or not the excised material is specifically recited herein.

Other embodiments are within the following claims and non-limitingexamples. In addition, where features or aspects of the invention aredescribed in terms of Markush groups, those skilled in the art willrecognize that the invention is also thereby described in terms of anyindividual member or subgroup of members of the Markush group.

1. A quaternary ammonium halide of Formula (I)

wherein: X is Br or Cl; R is selected from the group consisting ofC₁-C₂₀ alkyl, C₆-C₁₄ aryl, C₃-C₈ heteroaryl, C₃-C₂₀ cycloalkyl, andC₇-C₂₀ aralkyl; R′ is selected from the group consisting of C₁-C₂₀alkyl, C₃-C₂₀ cycloalkyl, C₇-C₂₀ aralkyl, and C₂-C₁₅ alkenyl.
 2. Thequaternary ammonium halide of claim 1, wherein R′ is C₁-C₂₀ alkyl. 3.The quaternary ammonium halide of claim 2, wherein R′ is


4. The quaternary ammonium halide of claim 1, wherein R′ is C₇-C₂₀aralkyl.
 5. The quaternary ammonium halide of claim 4, wherein R′ is


6. The quaternary ammonium halide of claim 1, wherein R is C₁-C₂₀ alkyl.7. A method of making the quaternary ammonium halide of Formula (I) ofclaim 1, comprising: reacting a tertiary amino primary alcohol with adihaloaliphatic compound or a dihaloaralkyl compound.
 8. The method ofclaim 7, wherein the tertiary amino primary alcohol isN—N-dimethylaminoethanol.
 9. The method of claim 7, wherein thedihaloaliphatic compound is 1,10-dichlorodecane.
 10. The method of claim7, wherein the dihaloaralkyl compound is α,α′-dibromo-m-xylene.
 11. Thequaternary ammonium halide of claim 6, wherein R is